Improvement in hot-air engines



2 Sheets-*Sheet 1.,

1. HmscH. Hot-Air Engines.

Patented sepi.15,'1874.

No.l55,0 87.

2 Sheetsf-Sheet 2. HIRSCH.

Hot-Air Engines. N0. 155,087. Patented Sept.'15, 1874.

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UNITED STATES PATENT OFFICE.

JosEFE Friesen, OF LYoNs, FRANCE.

IMPROVEMENT IN HOT-AIR ENGINES.

Specification forming part of Letters Patent No. 155,087, datedSeptember 15, 1874, application filed May 25, 1874.

To all whom it may concern'.-

Be it known that I, JOSEPH HIRscH, of Lyons, Department of the Ithone,France, have invented certain Improvements in Hot- Air Engines, of whichthe following is a specification:

The object of my invention is an improved engine in which to utilize, asa motive power,

the elastic force of hot air. I attain this object by causing the air topass alternately back and forth from one cylinder to another through apassage or regenerator, in which an extensive heating or cooling surfaceis obtained in a small compass, the air being intensely heated andexpanded by liquid or gaseous fuel in one cylinder, and cooled in theother; or being similarly treated on opposite sides of the piston of asingle cylinder, and being gradually cooled in its passage through theregenerator from the hot to the cold air chamber, Whilel on its returnto the hot-air chamber or cylinder it is as gradually heated by the saidregenerator, all as fully described hereafter, and as illustrated by theaccompanying drawing, in which- Figure 1, Sheet 1, is a sectionalelevation of my improved hot-air engine 5 Fig. 2, Sheet 1, a sideelevation; Fig. 3, Sheet 2, an end elevation; Fig. 4, Sheet 2, a planview; Fig. 5, Sheet l, a sectional plan on the line 1 2, Fig. l; Fig. 6,Sheet l, a detached view of part of Fig. 5 Fig. 7, Sheet l, an enlargedview of part of the apparatus.

On reference to Figs. 1 to 6, inclusive, K represents the frame of anengine, to which are secured two cylinders, A and H, the former, whichis the hot-air cylinder, being vertical, and the latter or cold-aircylinder inl" clined. The upper end of the cylinder A communicates withthe outer end of the cylinder H through a passage, a, regenerator J, andpassage b, which will be more particularly referred to hereafter. Theupper portion of the cylinder A consists of a body, B, of refractorymaterial, surrounded by a sheetmetal casing, B1, and the portion C ofthe piston C is also of refractory material, as are also the Walls a.'of the passage a, and walls I of the regenerator. The pistons C and G ofthe cylinders A and H are connected by rods D and F to cranks on themain shaft E of the engine, which is provided with a fly-wheel. (Notshown in the drawing.) The generator J consists of a net-work ofrefractory elements, through which the air is caused to pass in itspassage from one cylinder to the other.

These elements consist, in the present infractory material, of thecharacter illustrated in Figs. 5 and 6, arranged closely together, withspaces between them for the passage of the air, the object being toobtain as great an extent of heating and cooling surface as possible ina small space.

The refractory bars or plates can be made of earthenware, compressedmagnesium, porcelain, or other analogous material; or they may bereplaced by asbestus or Wire net-Work.

In some instances I prefer to subdivide the interior of the regeneratorinto several distinct vertical compartments, in order to diminish thelength of the refractory bars, and thus increase their strength.

Within the passage b, beneath the regenerator, is a segmental valve, bl,provided with a handle, b2, by the movement of which the valve can becaused to close more or less of the passage, and thus regulate the speedof the engine.

An air-pump, L, Figs. 1 and 4, is attached to 011e side of the cylinderA, and is operated from the main shaft E of the engine through themedium of gear-wheels d and d', a crank, c, and connecting-rod L. Thispump communicates with the passage b through a pipe, e, Fig. 3, and itsobject is to supply fresh air to the cylinder H to take the place of thecon- /sumed air, which is periodically expelled.

The heat is kept up in the engine by gaseous or liquid fuel, Which isforced into the cylinder A by a pump, M, and there ignited. If gaseousfuel is used, it is generated by the vaporization of hydrocarbon in anyWel1-kn0wn form of apparatus, and is supplied to the pump through apipe, j, Figs. 2 and 3, and is forced from the pump through avalve-chest, M2, pipe jl, and box f2, filled with Wire net-Work, intothe upper portion ofthe cylinder A.

The pump M derives its movement from the piston G of the cylinder Hthrough the medium of the following mechanism: The pistonrod of the pumpis connected, by a rod, M1,

stance, of groups of thin plates or bars of re .and adjustable block f,to the arm g of a rockter, is arranged directly beneath the cold cyl-Ainder H, as shown in Fig. 1, and communicates with the latterintermittently through a passage, k, the upper portion of the saidchamber above the water-level being maintained at a pressure whichvaries in accordance with the desired speed of the engine. A small pump,P, Fig. 2, operated by a rod, p1, connected to an arm, p2, of theabove-mentioned rock-shaft 7L, forces water through a pipe andsprinkler, Z, Fig. 1, into the cylinder H, for the purpose of coolingthe air therein; and this water, together with the consumed air, iscarried oif from the cylinder by the passage 7c into the chamber N atevery stroke of the pump, owing to the action of a projection, O2, onthe pump-rod p1, which strikes a springrod, O1, and thus operates avalve in a box, O, with which the said passage k communicates.

The operation of the engine is as follows: The temperature of the'cylinder A is first raised to the required degree by forcing first acurrent of hot air, and then gas or other Haines, through an opening,B2, with which the said cylinder is provided at the top. Thepressure-reservoir N is next filled with water up to the opening m ofthe escape-valve fn,

Fig. l, which will be more particularly referred to hereafter, thestroke of the gaspump M is regulated by an adjustment of the slide f,Fig. 2; the fly-wheel is turned one or more times, in order toreciprocate the pistons, and the operation begins. A combustible gas orliquid is first injected into the cylinder A, Where it is consumed,highly heating the air already in the cylinder, and forcing down thepiston. 0n the upward movement of the piston, the heated air passesthrough the regenerator J, which extracts a large proportion of theheat, and into the cylinder H, where the injected water reduces itsvolume, causing a partial vacuum, and operating the piston Gr. By thesesuccessive movements of the air, submitted alternately to greatvariations of temperature, the pistons are operated, the result of thevarying pressures being a uniform reciprocating movement of the saidpistons, and a positive rotary movement of the engine-shaft E. Theair-pump L, before mentioned, supplies fresh air to replace that whichis heated and expanded, and partly consumed at each revolution of theengine, and forced out of the cold cylinder through the passage k. Asthis consumed air, as well as the water of injectionfrom the coldcylinder, is continually stored up in the pressurereservoir N, it isnecessary that the latter should be provided with an escape-valve, bywhich a uniform pressure can be maintained, and the said pressureregulated in accordance with the required speed of the engine. For thispurpose I employ a valve, n, opening outward, and contained within abox, Q, which has a passage, m, communicating With the interior of thepressure-reservoir. The valve is maintained in its seat by a spring, n2,on a rod, nl, the pressure of which is regulated by a nut, a3. (SeeFigs. l and 7 The nut, rod, and spring are forced upward by a forkedbellcrank lever, R, Fig. 3, acted on in one direction by a spring, n4,and in the opposite direction by a centrifugal governor, R1, whichderives its movement from the engine-shaft E through two pulleys, R2 andR3, and a connecting-belt.

When the pressure in tbereservoirNexceeds the proper amount vthe valve awill be opened automatically, and will permit the gas and water toescape through the opening m1 and pipe m2 until the pressure has beenrelieved; and by means of the above-described governor I am enabled toregulate the speed of the engine by allowing an escape of pressure fromthe reservoir N when the speed is too great, and by permitting thepressure to increase when the speed of the engine slackens. Forinstance, if the speed increases, the governor will so vibrate thebell-crank lever It, Fig. 3, as to relieve the spring u2, andconsequently give freer play to the escape-valve n. If, on the contrary,the speed slackens, the lever R will be vibrated in the oppositedirection, which will compress the spring n2, and thus maintain thevalve more firmly in its seat.

It is necessary that the lower portion of the cylinder A as well as ofthe piston C, which are of cast-iron, should be maintained at acomparatively cool temperature; and for this purpose I form an annularwater-chamber, A', in the said cylinder, surrounding the piston, andpack the cylinder above and below this chamber with metallic packing p,to vprevent leakage. (See Fig. l.) Water continually vcirculates in thechamber A', and is supplied from the reservoir N through a pipe, q, Fig.3,

which communicates with an elevated reservoir, S, the latter having apipe, q1, leading to the chamber A', from which the water is conductedoff through a pipe, g2, communicating with the waste-pipe g3 of thereservoir S.

Although I prefer to inject cold Water into the cylinder H at a momentdetermined by the stroke of the piston G, for the purpose of absorbingthe heat which results from the compression of the air, I can substituteother equivalent cooling apparatus, arranged in the channel b beneaththe regenerator, or I can cause cold water to circulate around theexterior of the said cylinder H.

In the engine above described the interior Vpressure is always greaterthan that of the external air, and it is necessary therefore to use anair-pump, L; but, in some instances, I can simplify the apparatus byreducing the pressure, and dispensing with the air-pump,

`pressure-reservoir N, and Water-injector, the fresh air necessary forthe support of combusscribed, of the cold cylinder H, passage k,automatically-operated Valve, and the pressure-reservoir N.

4. The combination of the lower metallic portions of the cylinder A, itspiston, and the annular coolingchamber A', through which a circulationof cold Water is maintained, as described.

5. Thecombination of the cylinder H, outl let m, reservoir N, and itsspring-valve n, all substantially as and for the purpose described.

In testimony whereof I have signed my name to this specication in thepresence of two subscribing witnesses.

JOSEPH HIRSCH.

Witnesses EMILE RICHARD, GH. F. THIRION.

